I'm inside one of the reactors at Fukushima Daiichi Nuclear Power Plant, site of the worst nuclear disaster in history. It's pitch black, with only a flashlight to light my way. I glide over a metal catwalk, heading deeper into the reactor.  But then, when I turn to walk down the stairs, I hit an obstruction.

At that moment, a loud buzzer, like something out of an old game show, blasts into my ears, breaking the whole illusion.

OK, so I'm not actually in the Unit 1 reactor at Fukushima –- the radiation level at its core is high enough that even minutes inside would be a death sentence. I'm in a virtual reality setup at the Naraha Center for Remote Control Technology, about a half-hour drive south of the Daiichi facility.

Next to me are my photographer, an interpreter, a representative from Tokyo Electric Power Co. and an employee of the Naraha facility who's serving as our guide through this virtual re-creation. We're all staring at a giant screen projected on the wall just a few feet in front of us and to our sides.

Thanks to robot surveys and loads of data, this facility has been able to piece together a fairly accurate simulation of the Fukushima reactors. Tepco and the Japan Atomic Energy Agency have worked together to build this setup. But unlike other VR experiences, the virtual trip into the facility isn't for fun. Academics, engineers and Tepco employees use these simulations to get a sense of what kinds of robots can make it through the reactors, and which can't.

Eight years after an earthquake and tsunami combined to overwhelm Fukushima Daiichi, the plant remains shut down, with Tepco and the Japanese government struggling to find ways to remove the radioactive material.

This VR simulation marks one way to experience how bad things are inside -- without the cost and risk of actually entering the reactors. Virtual reality gets a bad rap these days as a much-hyped technology trend that failed to captivate consumers in a meaningful way. There are select instances that transcend the typical experience, from a mash-up of VR and immersive theater to projects that tap into your emotions, but for the most part, many consumers (and some CNET editors) have knocked VR as too expensive and not dazzling enough to be worth your time.

But the Fukushima experience illustrates how VR can move beyond entertainment and serve more practical needs. By offering a sense of what it's actually like inside those reactors, it's serving a critical role in the mission to decommission the reactors at Daiichi, a task that's estimated to take four decades and $75.7 billion.

"We believe that testing a developed technology … by using equipment similar to the real one before applying the actual facility, will make the construction on site more feasible," says Hideki Yagi, general manager of Tepco's Nuclear Power Communications Unit.

Gliding through a reactor

Unlike a typical virtual reality setup, which requires you to wear a large, bulky headset that closes you off to the real world, the Fukushima experience features a pair of 3D glasses.

Digital projection supplier Christie Digital Systems created the screens, which span the entire height and width of the wall, or nearly 12 feet each way. The screen extends to the left and right sides, which go about seven and a half feet back. There are five projectors hidden behind the screens, including one that shoots from above down to the ground beneath me.

The massive display, which offers a full-scale rendering of the facility, fully immerses you in the place. While no one would get into specifics about the price tag, Mike Garddio, a senior project manager at Christie, says something like this costs hundreds of thousands of dollars.

"It's not something you'll find at your local arcade," he says.

The rendering was put together through a combination of existing blueprints and laser mapping generated from data amassed by survey robots sent into the reactor buildings. As we get deeper into Unit 1, the details fade away, since no one really knows what's inside the core of the reactor and below, referred to as the primary containment vessel and the pedestal.

Itochu Techno-Solutions designed the user interface and application, which incorporated data from the JAEA and Tepco. The system includes data from Units 1, 2 and 3 at Daiichi, which all still have varying degrees of radioactive material and debris stuck in their cores.

"The accomplishment of this project was based on the know-how developed by providing simulation solutions in the engineering area, and thanks to support from JAEA and nuclear energy-related companies involved in Fukushima reconstruction," says Jumpei Asano, a spokesman for Itochu.

In our first run-through of the Unit 1 reactor, our guide was in control, wielding a one-handed controller that looked like a cross between a power drill and a phaser from Star Trek. Because Tepco wanted to keep the details of the reactor a secret, we couldn't film any of the footage.

After gliding through the reactor for a little while, our guide switches from just the flashlight to full lighting, giving us a better view of our surroundings. That initial flashlight view was important, though, since it gives operators a better idea of what the limited view looks like.

The experience is convincing enough that I feel a tingle in my body as we run through a wall. Our guide takes us up and down different parts of the reactor, which is a bit disorienting since your body knows you haven't actually moved.

The screen's orientation is tethered to the guide through a motion-tracking system attached to his 3D glasses, essentially making us passengers on his wild ride.

Entering the Matrix

After a few minutes of the guided tour, I don the main 3D glasses and take hold of the controller for my own trip.

For security reasons, the Naraha operator loaded up a mock simulation of a generic reactor space, allowing me to cruise around at my leisure.

VR is often compared to The Matrix, and I find the comparison apt with this system. The floors are white with a grid of black lines, and a gray structure houses an assortment of pipes I can navigate through. It's all very colorless.

I'm able to go forward and backward at the push of a button, and can turn or move up and down by moving my head in that direction. The experience is a lot smoother now that I'm in control, the screen and controls in sync with where I want to go.

A second button allows me to "grip" objects in the virtual world and bring them around the space. If the object doesn't fit through the pipe, I hear that buzzer.

My experience isn't exactly a tour of one of the Fukushima reactors, but it does offer me a glimpse at how such a tool could help train operators to pilot a robot through the real thing.

That's a heck of a lot more useful than some gimmicky VR stunt tied to an upcoming movie.

The story originally published on March 6 at 5 a.m. PT.